"What some folks will do does not change my advice."

I kind feel this way too. But I often get complaints when my advice is above the "heads" or capabilities of the average keeper, or perceived unsafe for the less experienced that may be reading, or too much to ask of the average keeper to have time or dedication for. Just enforcing the standard I've been subjected to for so long.

Yes, "soft bodied" or smaller crickets are "relatively" easier on digestion. The exoskeleton of older crickets contain more chitin, the chitin is more solidified, and there is also the prey size complication by itself. Wild caught crickets or crickets exposed to UV have darkened and even more hardened exoskeletons. Chitin is a strong natural polymer, composed of a nitrogen containing polysaccharide ( carbohydrate ). It is used in resins, a thickening agent for foods, and in temporary sutures. So it is biodegradeable, but takes a while to break down. Then there is the fat content and type as well. So the smallest/youngest crickets available is the wisest choice, even if it costs more money to buy them that way.

There are indeed differences is descriptions and sizes of crickets at different places. Usually smaller local shops carry a wider variety of sizes to cater to specific demands. The larger corporate stores don't think this is cost effective catering to a niche or type of reptile that needs smaller than the "small" size they carry. They tend to push sales of fruitflies instead. I usually buy at Petco, but it requires that you get your crickets a day or two after they get a fresh shipment. This is when you will find the really small one's mixed in, and it helps to know somebody working there who will go through the trouble of picking out the smallest crickets for you.

There are several complicated methods and formulas for determining the standard metabolic rate of a reptile ( also commonly referred to as basal rate (BMR) or minimum energy cost ( MEC ). One method includes monitoring oxygen consumption, CO2 production, body temp., heart rate, and flow volume. This method is known as gas exchange stoichiometry, and has been called into question as being less accurate than the more complex bioenergetic energy transfer methods of explanation, which factor in almost every bodily process in mathematical form through reaction pathways ( reactants, products, synthesis, etc ) to render the answer.
Two slightly less species or individual accurate, but far easier approximations of minimum metabolic requirements are:

Y = K (M)0.75
Y = the resting animal's energy output in kilocalories (kcals) per 24 hours
K = a taxonomically dependent constant, and
M = animal's body mass in kilograms.

K for reptiles being a value of "10"

An easier expression of the SMR/BMR/MEC formula is:

(kcal)=10xWt.kg 0.75

( wt. in gm. divide by "1000" ) scientific calculator function "x^y" enter ".75" x "10"

Another even easier given by M. Kaplan is ( wt. x wt. x wt. )sq.rt.)sq.rt.)x 10

Example: a 50 gram Horned Lizard
50/1000=.05kg
"x^y" .75=0.1057
.1057x10=1.057 kcals/d

So the 50 gram HL requires approximately a little more than 1 kcal ( 1 calorie ) per day to meet minimum energy requirements at rest, at optimal body temperature!

Fluker's gives a different formula of ( wt. kg ).77x32 @86*F body temp.

Not sure where they get that, I found another source from a DVM which is similar but gives the .75 x^y factor, rather than .77. But it renders an answer of 3.186 kcal/d, just over twice as much as the first 2 examples. Hence, probably why they recommend 50% of SMR in kcal/d for emaciated reptiles considered "severe". So according to Fluker's a severely emaciated reptile of 50grams should receive 1.59 kcal/d. Nearly the same figures.

For emaciated or sick reptiles in moderate condition that will not eat on their own, I may force feed small prey. If they are in more serious condition, I use a puree of blended prey along with saline and/or Pedialyte, and I've even used Gerber baby food such as chicken puree through a stomach tube and syringe. If I cannot approximate the calories reliably, then I try to go by Kaplan's 2% of body weight per day recommendation, give or take. In the example above, it would be 1 gram/day for a 50gm HL.

It is preferred to treat most emaciated HL's with ants, though I don't have the caloric information available on them yet. But for treating an emaciated HL with crickets: The cricket (Acheta domestica) may vary between 1.5-5.0 calories (kcals) per gm. depending on hydration and gut loading state. The lower end of the scale is for normally hydrated and feed crickets. So it doesn't take much to meet metabolic/caloric requirements.

If the lizard is warmer and more active, just a little under weight, then up the caloric intake 25-50% above SMR. If it's sick and less active then you should stay closer to the SMR figures and not overwork the system.






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"A man that should call everything by it's right name, would hardly pass the streets without being knocked down as a common enemy." The Complete Works of George Savile, First Marquess of Halifax 1912,246

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